1. Field of the Invention
The present invention relates to a production schedule planning device for scheduling a processing order and progress of products in various production lines, and a method of producing semiconductor devices using the same.
2. Discussion of Background
In general, a production schedule planning device, used in various production lines, receives results of progress in processing existing lots, which are momentarily changing, in addition to information of newly thrown products (i.e. lot), and repeatedly performs calculations of the plan based on the information. FIG. 8 illustrates a generally-used conventional production schedule planning device. In FIG. 8, numerical reference 1 designates data of past result information, which are data of progress in processing lots, and numerical reference 2 designates data of process information, obtained in processing the lots. These data 1 and 2 are usually held in a system other than the production schedule planning device, wherein the production schedule planning device has a data interface unit (hereinbelow, referred to as data I/F), designated by numerical reference 3. A schedule planning unit 4 plans and calculates a production schedule based on data, obtained from the data 1 of the past result information and the data 2 of the processing information. Numerical reference 5 designates a schedule outputting unit, which outwardly outputs the schedule, planned in the schedule planning unit 4.
FIG. 9 illustrates a processing flow of the conventional production schedule planning device, which is generally used. In step S6, information of the newly thrown lot is obtained. In step S7, past progress of the existing lots is obtained. In step S8, information of processes of these lots is obtained. In step S9, a production schedule is planned based on the information. Thereafter, in step S10. The plan is outputted.
The generally-used production schedule planning device plans the schedule based on the information of progress of the products. Therefore, when a lot is newly added and/or a difference between a schedule and a past result happens, there are problems that the schedules for all lots should be reviewed, and a time for calculating the schedules is drastically increased. Further, schedules for other than the products, of which past results differ from the schedules, are also changed, whereby the schedules are changed from those in an initial stage of the plan, and confusion is caused to production lines.
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide the production schedule planning device having a data interface unit for receiving data from an outside; a schedule planning unit for planning and calculating a production schedule based on the external data, obtained from the data interface unit; and a schedule outputting unit for outwardly sending the schedule, planned in the schedule planning unit, wherein the production schedule planning device has a function of planning a schedule for newly thrown lots without making the schedule planning unit obtain current progress and/or information of initial setups of processing devices and without modifying and/or changing a previous schedule by recognizing the previous schedule as a postulate.
According to a second aspect of the present invention, there is provided the production schedule planning device, in which the schedule planning unit has time axes respectively for the processing devices and also has a function of scheduling while inserting space times in the schedule, which space times are generated by predetermined timing.
According to a third aspect of the present invention, there is provided the production schedule planning device further comprising: a lot-deletion and modification instructing unit for deleting data of unnecessary lots and lots to be modified in the previous schedule.
According to a fourth aspect of the present invention, there is provided a method of producing semiconductor devices using the production schedule planning device, described in any one of the first through the third aspects of the present invention.